PER_EXT_SEC_HISTORY_ASSIGNMENTS_UE showing duplicate rows

Summary:

What threading database item should i use for changes only using PER_EXT_SEC_HISTORY_ASSIGNMENTS_UE as it is showing duplicate rows when i use Extract Historical Assignment ID as the threading database item?

Content (required):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):